curl: add --fail-with-body

Prevent both --fail and --fail-with-body on the same command line.

Verify with test 349, 360 and 361.

Closes #6449

docs/cmdline-opts/Makefile.inc

@@ -5,7 +5,7 @@
 #                            | (__| |_| |  _ <| |___
 #                             \___|\___/|_| \_\_____|
 #
-# Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+# Copyright (C) 1998 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
@@ -61,10 +61,11 @@ DPAGES =					\
   dump-header.d					\
   egd-file.d					\
   engine.d					\
-  etag-compare.d                \
-  etag-save.d                   \
+  etag-compare.d                                \
+  etag-save.d                                   \
   expect100-timeout.d				\
   fail-early.d					\
+  fail-with-body.d				\
   fail.d					\
   false-start.d					\
   form-string.d					\

docs/cmdline-opts/fail-with-body.d

@@ -0,0 +1,16 @@
+Long: fail-with-body
+Protocols: HTTP
+Help: Fail on HTTP errors but save the body
+Category: http output
+Added: 7.76.0
+See-also: fail
+---
+
+Return an error on server errors where the HTTP response code is 400 or
+greater). In normal cases when an HTTP server fails to deliver a document, it
+returns an HTML document stating so (which often also describes why and
+more). This flag will still allow curl to outputting and save that content but
+also to return error 22.
+
+This is an alternative option to --fail which makes curl fail for the same
+circumstances but without saving the content.

docs/cmdline-opts/fail.d

@@ -2,6 +2,7 @@ Long: fail
 Short: f
 Protocols: HTTP
 Help: Fail silently (no output at all) on HTTP errors
+See-also: fail-with-body
 Category: important http
 ---
 Fail silently (no output at all) on server errors. This is mostly done to

docs/options-in-versions

@@ -59,6 +59,7 @@
 --expect100-timeout                  7.47.0
 --fail (-f)                          4.0
 --fail-early                         7.52.0
+--fail-with-body                     7.76.0
 --false-start                        7.42.0
 --form (-F)                          5.0
 --form-string                        7.13.2